Bug ID 1759097: F5OS STP with LAG sends BPDU on single interface regardless of member interface status

Last Modified: Jul 15, 2026

Affected Product(s):
F5OS F5OS-A(all modules)

Known Affected Versions:
F5OS-A 1.8.0, F5OS-A 1.8.1, F5OS-A 1.8.2, F5OS-A 1.8.3, F5OS-A 1.8.4

Fixed In:
F5OS v2.0.0

Opened: Dec 06, 2024

Severity: 2-Critical

Symptoms

BPDU packets are transmitted on only one LAG member interface even when that interface is down. Traffic does not pass even though everything seems in the correct state.

Impact

Traffic is disrupted.

Conditions

F5OS system configured with Link Aggregation Groups (LAG). LAG interfaces participating in Spanning Tree Protocol (STP/RSTP/MSTP). Multiple physical interfaces configured as LAG members. One or more LAG member interfaces become disabled or go down.

Workaround

None

Fix Information

Enhanced STP to properly monitor LACP state changes and select active LAG member interfaces for BPDU transmission. System now detects and reacts to LACP state changes in real-time, ensuring BPDU packets are sent on operational LAG member interfaces only.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips